The ultimate goal of this SBIR is to identify genes that are regulated by the putative transcription factor encoded by the human PAX-6 (aniridia) locus. The specific aim of Phase I is to use bacterially produced pas-6 protein to identify specific binding sites in human genomic DNA. Isolation of sequences bound by pax-6 will be achieved by making fusion proteins of pax-6 with the maltose binding protein, and purifying protein/DNA complexes on amylose columns. Genomic fragments that include recognition sites for pax-6 will be screened for the presence of sequences expressed in the retina and the developing brain. At the end of Phase I, clones representing tissue specific targets of pax-6 binding will be obtained. These materials will facilitate cloning of novel genes that are regulated by pax-6. Since PAX-6 and other PAX genes are known to be mutated in human development disorders, cloning of target genes will permit the study of transcriptional mechanisms involved in the molecular pathology of these disorders. In addition to furthering knowledge of disease mechanisms, this research has important implications for manipulating gene expression in the nervous system. PROPOSED COMMERCIAL APPLICATION: The identification of genes that are regulated by pax transcription factors will lead to understanding of the molecular pathology of inherited disorders such as aniridia and Waardenburg's syndrome, thereby providing a direction for gene therapy research. Since many pax genes are involved in neural development, understanding of their transcriptional mechanisms may also be of general applicability to therapeutic programs requiring targeted gene expression.